We propose a novel wavefront sensing technique based on binary-aberration-mode filtering and detection. Rather than Zernike polynomials, the orthogonal binary two-dimensional Walsh functions are transferred to circular mode-fieldfitted Walsh functions and used as binary aberration modes to expand the wavefront. A Digital Micromirror Device (DMD) is employed as an intensity spatial light modulator (SLM). It generates each of the intensity modulation patterns prescribed by the mode-field-fitted Walsh functions to modulate the intensity of the incident beam before it is focused to impinge on a single-mode optical fiber. The single-mode optical fiber, as a spatial mode filter, supports only fundamental binary aberration mode. A detector collects the amount of the intensity after each modulation. By building the relationship with the intensity, the binary-aberration-mode coefficients can be calculated. This technique turns the complex two-dimensional wavefront sensing into simple intensity detection. Therefore, many limitations, such as low response frequency and weak far-infrared detection capability of most photosensor arrays can be easily eliminated just by adopting a photosensor such as a photodiode. Thus, this technique is especially suitable for weak and far-infrared light detection. The numerical simulation demonstrates that the wavefront reconstruction with the binary aberration modes is reliable and the technique can easily meet the demands of high speed atmospheric measurements and has a promising application in atmospheric fields.

英文摘要:

We propose a novel wavefront sensing technique based on binary-aberration-mode filtering and detection. Rather than Zernike polynomials, the orthogonal binary two-dimensional Walsh functions are transferred to circular mode-fieldfitted Walsh functions and used as binary aberration modes to expand the wavefront. A Digital Micromirror Device (DMD) is employed as an intensity spatial light modulator (SLM). It generates each of the intensity modulation patterns prescribed by the mode-field-fitted Walsh functions to modulate the intensity of the incident beam before it is focused to impinge on a single-mode optical fiber. The single-mode optical fiber, as a spatial mode filter, supports only fundamental binary aberration mode. A detector collects the amount of the intensity after each modulation. By building the relationship with the intensity, the binary-aberration-mode coefficients can be calculated. This technique turns the complex two-dimensional wavefront sensing into simple intensity detection. Therefore, many limitations, such as low response frequency and weak far-infrared detection capability of most photosensor arrays can be easily eliminated just by adopting a photosensor such as a photodiode. Thus, this technique is especially suitable for weak and far-infrared light detection. The numerical simulation demonstrates that the wavefront reconstruction with the binary aberration modes is reliable and the technique can easily meet the demands of high speed atmospheric measurements and has a promising application in atmospheric fields.